I know, I know. After a long winter, you are anxious to get out into the garden and start planting. It’s been beautifully warm for several days, surely it’s time to start gardening. Right? Wrong.
I hate to burst your bubble, but you really need to pay attention to last average frost dates for your area. Every year, about the 1st week of May, I have a dozen people asking me if they can start their garden. The answer: Probably not. Because no matter how nice the weather is on May 5th, I promise you that sometime before May 20th there will be a cold snap–or worse, a snow storm. It happens every year. Always.
So when can I start gardening?
First find out what the average last frost date for your area is. Do not plant any cold-sensitive plants, like tomatoes, peppers or melons, before that day. In fact, you probably should wait an extra 5-10 days after the average last frost day to plant cold-sensitive plants. You want to make absolutely sure those tender plants don’t meet an untimely death.
But there are vegetables you can plant before the average last frost date. Cold tolerant plants include all your brassicas, peas, most root crops and lettuce. These can all tolerate some frost. In fact some, like peas and most brassicas actually do quite well with a little frost.
So start by planting peas and onion sets. Then plant your brassicas. Then radishes and beets followed by lettuce. After that carrots, Swiss chard and potatoes. By now we are getting towards late May and frost is unlikely. So go ahead and plant corn, beans, cucumbers and summer squash. Finally, at the end of May, when there’s little danger of frost, plant all those tender plants: tomatoes, peppers, melons and winter squash. Be ready to protect these plants with a blanket or cloche if an untimely cold snap is predicted. But by Memorial Day, a killing frost is unlikely.
Use a planting guide
This year I bought this handy dandy planting guide. It was just $3 with my seed order and it tells me when to plant all my plants, not just for spring planting but for fall planting as well. Or you can refer to online sources to see the best time to plant each crop. This page asks you to enter your zip code and then tells you exactly when to plant each crop.
Protect your plants from frost
So let’s suppose you follow the planting guide and plant all your plants when the experts tell you. And then along comes a freak early summer frost. But all is not lost. You can still protect your plants from frost and get them through a few nights of freezing weather. First, fill up a 5-gallon bucket with water and let it sit in the sun all day. The water will soak up the sun’s heat and act as a thermal mass. During the night it will slowly radiate that heat, raising the surrounding temperatures 2°-3°. That’s not a lot, but it might be just enough when the temperatures get a little iffy. You can increase the effectiveness of this thermal mass by covering that row, along with the 5-gallon bucket of water, with a blanket.
More ways to protect your plants
Here are some other ways to protect plants from the cold and extend your growing season. I’ve listed them from easiest and least expensive to more involved and/or more expensive methods. Follow the links for more details on these different methods to protect crops.
- Use old bed sheets or floating row covers (a special, light weight non-woven fabric.) Lay these over tender plants to prevent frost damage. At the end of the growing season, plants are bigger or more mature. That’s when you can use blankets or tarps to cover the plants.
- Cloche is French for “bell”, so think of a bell (or bowl) placed over plants to keep
heat in and cold out. It can be as simple as a 1-gallon plastic jug with the bottom cut out. Or you can use any clear glass bowl turned over the plant. Shop thrift stores for glass punch or mixing bowls. Or look for discarded fish tanks on the boulevard during your town’s spring clean-up week.
- Wall-o-Water is one of the most popular cold-protection products on the market. Read about how well it worked for our tomatoes.
- A cold-frame is a wooden frame with a window on top that acts like a green house. It is easy to construct and if you use cast off materials found during clean up week, it will only cost a few dollars. (Read here how successful the cold frame was for us this year.)
- Create a mini green house with a hoop house, made with PVC pipe and clear plastic.
Extend your growing season at the beginning and the end
You can use these same techniques at the end of the growing season. In September we usually have several nights of cold temperatures followed by another 2-3 weeks of glorious weather. It’d be a shame to lose those last 2-3 weeks of gardening just because of a couple cold nights.
With our short growing season here in the Midwest, we want to get the most out of our gardening that we can. Protecting your garden now will get you into the garden earlier this spring. And if you protect them in the fall you will have fresh veggies long after all your neighbors’ gardens will have perished in the cold. So protect your plants to make sure you are getting every last drop of garden you can out of the season.